I have enough knowledge and many years of experience in electronics and engine to change the O2 sensor signal and do it safely.
My problem is I actually need TIME to get in and experiment and test this extensivly.
As soon as I am done getting my house finished, on the market & sold, I'll have extra time & money for research on subjects such as this.
So far, no one has been selling time OR sleep on ebay. I think if someone could market these two items, they'd be RICH!
LOL
Well... suit yourself... I think it's probably above your head... but I really don't know what you are capable of doing..... you need to make a complex resistor bridge to modify the O2 sensor without loading it or it will go nuts and your ECU will stop using the O2 sensor. (which will make it run worse.... and move into a much richer fuel map... it will make less power and use way more fuel )
The best solution is to sample the O2 voltage with an analog to digital converter and then modify it via a microcontroller and drop it onto the ECU with a digital to analog converter. (basicly what a S-AFC would do)
This would require the use of something like a PIC microcontroller.... which is cheap ( $4 ) but you need an EEPROM burner and experence with PIC programming to make it work.
I suppose there are simple "voltage mirror" circuits which would work.
Basicly the O2 sensor signal goes into one side of the device and on the other side the chip puts out the exact same voltage which then can be modified using a resistor network without risk of loading the O2 sensor.
Who knows.... it might be possible to modify the signal with a simple resistor network (parallel and series combinations or an H-Bridge) but you will probably find that even with the use of Megohm resistors the O2 sensor won't function correctly.
The voltage mirror input will typically have impedance levels into the gigaohm area so it doesn't load the O2 sensor at all.
It's a simple circuit I could put together on a prototyping breadboard in about 15 minutes but I don't have a car to test it on.
If we could find out if my U20SED (optra 5) engine uses the same O2 sensors as the Legnaza T22SED engine then I could do some modifications when I take it to the dyno ( which should be sometime in the next month or so)
We plan to run the Optra 5 stock as a baseline and then drop in things like a Nubira ECU and cold air intake to see what kind of power we can make.
It would be easy for me to make a circuit and tinker with the O2 sensor data while reading out the wide band O2 sensor information on the computer.
But this certainly won't help you if your O2 sensor is a different make than mine.
Erfinder wrote:... but I really don't know what you are capable of doing...
Erfinder wrote:This would require the use of something like a PIC microcontroller.... which is cheap ( $4 )
Got those...
Erfinder wrote: but you need an EEPROM burner and experence with PIC programming to make it work.
And that.
But... You don't need an EEPROM burner. I'd suggest either a AVR Processor from Atmel or a Parallex Stamp. Both of which are Flash based and can be programmed via a serial port or parallel port with no need for an EEPROM programmer.
The Stamp is easier and programs in basic. However more expensive. The AVR is pretty simple and if you get the right carrier board, as easy to use as the Stamp. You can get an AVR Board and processor for under $50, probably cheaper. The Stamp is around $100.
As I said before, I'll have more time to experiment after I get my house sold.
Do either of those have A/D or D/A converters onboard?
I think I was looking into the Atmel processor at one time but I can't remember why I didn't like it..... it might have had something to do with the power supply requirements as most of the devices I manufacture run off small batteries.
I've allways worked with PIC's, there is so much free source code it makes it really easy to do virtually anything.
I don't write much code anymore.... I have free access to a site with virtually every piece of PIC code available to man.
I wrote a new logarithm calculator program for this guy who works for Motorola.... it decreases the size of the look up tables by an exponential value depending on how many digits of accuracy you need.
It's not very efficent for one or two digits of accuracy but by the time you hit about 4 digits it kills anything else out there.... it makes use of the ability to mutliply and divide logarithmic numbers.... basicly it uses multiple look up table numbers and multiplies or divides them to get the answer.
I don't know if he integrated it into his core functions but he really liked the level of accuracy it provided ( it uses very little RAM space but it is very complex so it takes a pile of processor power )
I also program in assembly language ( machine code ) I hate programming in basic.... waists so much time and limits what you can do.
What I can do in say 100 lines of assembly code would take perhaps 400 lines in Basic...... I should clarify that.... perhaps it might take 25 instructions in Basic but when the Basic compiler converts it to machine code those 25 instructions balloon into 400 lines of machine code.
Basic, C, Pascal, are all great languages but they are designed as a form of script so they need all kinds of extra crap to make them compatable with other commands.
It's hard to explain unless you've programmed in assembly language... these days everyone uses script languages and "module" of programming code because of the shear size and complexity of the programs.
Something that might take Microsoft guys a week to program in Visual C++ might take four months in Assembly language.
If done in Assembly language there would be no "bugs" the program would be smaller and run way faster but when you compare a week of programming time vs 4 months it's pretty obvious which way the software company will go.
I'm decent at programming in Intel, PIC assembly language, Basic, Visual Basic, C++, Visual C++, Fortran and Pascal but my advanced programming courses were in C++ so it's my "script language" of choice.
Anyways... I'm getting off topic.... I can probably find the sheet comparing the O2 sensor voltage vs A/F ratio.... I think I have it somewhere on my computer..... it's for the Nubira but it probably is the same for the Leganza..... should you ever want to fool around with this type of project.
Oh... you had the deluxe version... I had a VIC 20 with a tape as the data player
I used to make my own games.... but they pretty much sucked ass
I made a version of Centipede once... it was the only cool game I ever made.
My next computer after that was a MAC Plus.... which is still sitting on one of my desks....about 5 feet away... I still have the monster sized 10MB external hard drive.... it's about 8" in diameter
It's funny to see how things have changed.... my RIO Nitrus MP3 player has a 20GB hard drive the size of your thumb nail !
One of these days I'm going to have to plug in the old Mac and see what I've got on there.... it hasn't been turned on in about 15 years
It's not worth it to sell it.... I just can't seem to part with it.
Way off topic here, but, I still have my first home computer ... LOL ... a 1979 Timex Sinclare 1000.
I had the cassette drive, the 5" gray scale display AND the 15k upgrade cartridge!!
Back on topic ... after thinking about the cost of R&D and buying the parts I don't have on hand, it may be more cost effective to buy the Apexi; maybe even disect it and see how it works. They have allready done the work, and put it with a nice vacuum display that will fit in a single DIN slot under the CD player in the car.
I'm not going to dismiss looking into the data from the O2 sensor as I am interested in how something may be made more user friendly.
Cliff
Last edited by TheGreatAndPowerfulOz on Mon Sep 06, 2004 5:14 am, edited 1 time in total.
Ok as fro the type of sensors , they are gm sensors(ac delco) and are found in all gm cars that us e map sensors. It is a 1 bar map sensor that is found in all n/a gm cars, I will do a full write up on the install of the s afc tonight
You also need to knw that it is not the o2 signal that is modified, it is the map sensor signal that is modified. i will explain it all later on tonight. They are simple to install and i will explain later
I would think that it is going to limit the ability of the S-AFC's ability to change A/F ratios
If it only modifies the MAP the ECU will compensate when looking at the O2 sensor levels.
If the O2 sensor data was changed so the ECU saw what ever the S-AFC wanted it to then the ECU would simply be happy and not want to change anything.
Modifying the O2 sensor information is the only real way to make the car move from a rich to lean condition.... the ECU will allways try to make things push towards the same rich condition.
I really haven't looked at the S-AFC so I don't know what it connects up to.
Does it run the injectors off the S-AFC directly or does it still use the ECU to trigger pulse width??
I wasn't sure if it used it's own fuel and ignition timing maps or if it simply modified the ECU to force it to do what it wants.
You will have to be sure to document how the install went.... and I wish you good luck......
Does anyone know where I can find an instalation and instruction manual for the S-AFC online?? (I haven't checked around yet)
Ok so if I don't change anything will my car be ok. I have not done any Fuel mods on my car. It runs a little rich. If I run some octane boosters through and clean the plugs will I be ok. I can get an adjustable fuel pressure controller that will fit directly into my car. What should I do. I don't want high performance on this just performance that is going to keep my engine running OE in the fuel department.
ok I know that fuel boss does not work, but magnetics have a lot of effect on carbon. think of how the poles have effect on the earth. with out them there would be no life on this planet. I'm not backing the product but don't ever say that magnetics don't have effect on carbon (the basis of fuel). Yes I know that all fuel has so many additives in it that the carbon is reduced. But magnetics effect most organic compounds on the earth. Do some reading on magnetic fields before making a judgement. And to finish this off, don't buy the fuel boss unless you know something I don't about it.
also could my air intake ( see gallery) or my new exhaust (see gallery) be affecting the emissions. Could using a fuel treatment help ie. stp, slick 50, prolong. Should I just replace my O2 sensors? I need help.
